Sound-box.



EQR. JOHNSON.

SOUND BOX.

APPLICATION FILED MAR. 14, 1903.

Patented Nov. 24, 1914.

WITNESSES: INVENTOR:

5 A/WMW ATTORNEY:

ED STAiEs PA ELDRIDGE n. aonnson, or PHILADELPHIA, rEnnsYLvAnIa, assienoa 'ro VICTOR TALKING Macs-111w: oomranr, a cozarona'rron ornnw JERSEY.

SOUND-BOX.

Specification of Letters Patent.

To all whom it may concern Be it known that I, ELDRIDGE R.'JOHNSON, a citizen of the United States, and a resident of the city of Philadelphia, county of Phila delphia, 'and State of Pennsylvania, have invented certain new and. useful Improvements in Sound-Boxes, of which the following is a full, clear, and complete disclosure, reference. being had to the accompanying drawings, forming a part of this specification. i

The main objects of this. invention are .to provide in a sound'box an improved casing; an improved mounting for a diaphragm; and other improvements as will appear hereinafter.

In the accompanying drawings Figure 1 is a longitudinal central section of a sound box constructed in accordance with this invention; Fig. 2 an enlarged fragmentary front elevation of the diaphragm and its mounting;'Fig. 3 a transverse section on a radial line of Fig. 2 and Fig. 4 a front elevation of a diaphragm mounted in a con-' tinuous ring.

Referring to the drawings, the improved sound box comprises a casing having the usual tubular portion 1, projecting rearwardly from the box, communicating with the interior of the box, and whereby the box may be attached to the usual tubular support. Integral and concentric with this tubular portion 1, is an annular plate 2 form'- ing the back of the casing arid having a forwardly, tapering conical peripheral surface 7, concentric with and approximately parallel to the longitudinal axis of the box, which fits tightly into a corresponding tapering socket in the rear side of the front portion 3 of the casing, forming a tapering joint, the two portions being driven or forced together by suitable pressure.

Mounted uponthe inside of the front portion of the casing, and projecting ,through an aperture in the side thereof, is a stylus bar 4, carrying the usual stylus 5, held in place by a set screw 6, which projects forwardly through the front of the casing.

.The interior portions of the front and back of the sound box casing are recessed to form a diaphragm chamber, providing oppositely arranged internal circular flanges 8 and 9, adapted to cooperate to hold in position the ring or support 10, which carries of a suitable elastic cement. This groove is preferably made about .01 of an inch indepthand about .005 of an inch wider than the thickness of the diaphragm, which is usually-about .005 of an inch; thus leaving a space in the groove about .0025 of an inch wide on each side of: the diaphragm, and

Patented Nov. 24, 191 4. I

the diameter of the diaphragm-is such as to leave about the same width of space between its" peripheral wall and the bottom of the groove. This space in the groove between the diaphragm and the ring is filled .with an elastic cement which is preferably inserted after the diaphragm is in position, by means of a small syringe or similar tool, the cement beingbrought into contact wit the peripheral Wall ofthe diaphragm an with a narrow annular marginal area of each side of the diaphragm.

As the diameter of the diaphragm is larger than the internal diameter of the ring in which it is 'mounted, the ring is preferably constructed in split form, being divided transversely, as at 14, to permit the ring to be sprung open to receive the diaphragm. After the diaphragm is in place in the ring; the ends of the'ring may be joined by soldering, or brazing, or otherwise, and the cement above described.

Instead of a split ring a continuous ring 10' may be made of malleable metal, such as tin, and of internal diameter suflicient to admit the diaphragm 11 without the expansion of the ring, the rim being provided with an internal 'circum erential groove as heretofore described. When such a ring is then inserted as,

is used, the diaphragm is placed within the ring opposite the groove therein and the ring is then compressed radially in a suitable machine, reducing the diameter of the ring until its internal diameter is less than he diameter of the diaphragm. The diaphragm is then held centrally in position in the groove, and the spacebetween the .in the ring 10 by either of the methods above described, the ring is then placed in the tapered recess in the front portion 3 of the box, with its periphery engaging the tapered surface 7, near its outer edge, and is forced into its ultimate position, as shown in Fig. l, by the back portion 2, Whose flange 9 is cooperative With the flange 8 of the portion 3, to form a groove in which said ring 10'is rigidly retained. i

The sound box constructed in accordance with this invention is simple in design, easy to manufacture and may be quickly and easily assembled or taken apart, and the diaphragm is protected from injury and is free to vibrate Without being influenced by any degree of pressure that may be brought to bear between the portions of the casing that hold the diaphragm mounting in place.

Having thus fully described my invention, What I claim and desire to protect by Letters Patent of the United States is 1. A diaphragm supporting ring having a diaphragm receiving groove in its inner surface, said ring having a greater internal diameter than the diameter of the diaphragm, and being adapted to be contracted about the diaphragm to a smaller internal diamealiases ter than the diameter of the diaphragm to retain the diaphragm in the groove.

2. A diaphragm supporting metal ring having a diaphragm receiving groove in'its inner surface, said ring having a greater internal diameter than the diameter of the diaphragm, and being adapted to be contracted about the diaphragm to a smaller internal diameter than the diameter of the diaphragm to retain the diaphragm in the groove.

3. A diaphragm mounting ringhaving a longitudinal groove in its inner surface, said ring being split transversely with its ends spaced apart and being of a size to pass freely over a diaphragm, the distance be tween said ends being sufiicient to permit the ring to be contracted to receive the diaphragm in said groove.

1-. A diaphragm supporting ring having a diaphragm receiving groove in its inner surface, said ring being split transversely and having when its ends are spaced apart, a

greater internal diameter than the diameter I of the diaphragm, and having when its ends are brought together a smaller internal di- .a

ameter than the diameter of the diaphragm. In witness whereof I have hereunto set mv hand this second day of March, A. 1).,

ELDRIDGE R. JOHNSON.

Witnesses J. H. Woomvonrn, V. S. WOODWORTH. 

